Mobile devices (e.g., smart phones, tablets) often perform audio signal processing. Various audio signals (e.g., phone calls, music, radio, video, games, system notifications, etc.) may need to be mixed or routed in mobile devices. Different strategies may be implemented to control the mixing or routing of audio streams. For example, music playback may be muted during a phone call and then resume when the phone call is finished.
Information about spatial location of a simulated audio source to a listener over audio equipment (e.g., headphones, speakers, etc.) is often determined using head-related transfer function (HRTF) parameters. HRTF parameters are associated with digital audio filters that reproduce direction-dependent changes that occur in magnitudes and phase spectra of audio signals reaching left and right ears of the listener when the location of the audio source changes relative to the listener. HRTF parameters can be used for adding realistic spatial attributes to arbitrary sounds presented over headphones or speakers.